From 'memory' + '-ize,' from Latin 'memor' (mindful) — originally 'to make memorable,' then 'to learn by heart.'
To commit to memory; to learn something so that one can remember it perfectly.
Formed in English from memory (from Anglo-French memorie, from Latin memoria, from memor meaning mindful, remembering) with the verbal suffix -ize (from Greek -izein). The Latin adjective memor derives from PIE *men- (to think, to remember), one of the richest roots in the entire PIE system. The same root produced English mind, mental, mention
When 'memorize' first appeared in the 1590s, it did not mean 'to learn by heart.' Shakespeare used it in Henry VI, Part 1 (c. 1591) to mean 'to record for posterity' or 'to make memorable' — the opposite direction of the modern sense. The shift from 'to cause to be remembered' to 'to commit to one's own memory' happened gradually over the 17th and 18th centuries.